Road structure – process – or apparatus – Apparatus – Automatic control
Reexamination Certificate
1998-10-27
2001-05-08
Will, Thomas B. (Department: 3673)
Road structure, process, or apparatus
Apparatus
Automatic control
C404S084100, C404S118000
Reexamination Certificate
active
06227761
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates generally to methods and devices for contouring or smoothing freshly poured concrete, sand, gravel, dirt, or other like loose, spreadable materials, and, more particularly, to an apparatus and method for contouring and placement of such materials with a vehicle either positioned adjacent the materials to be contoured or driven through the materials to be contoured.
In the past, the screeding or smoothing of uncured concrete by screeding machines has been primarily limited to flat, one or two dimensional surfaces. In order to screed a three dimensional concrete surface, the screeding apparatus was required to follow predetermined or preset forms, such as wires, boards, or rails, stationed along both sides of the surface to be screeded. Each end of the screed would follow the predetermined physical form By using preset physical forms of different shapes or slopes on either side of the surface to be screeded, it is possible to create a smooth surface having a three dimensional curvature. The use of preset physical forms, however, presents several disadvantages.
The creation of the physical forms is a labor intensive process that increases the time and expense necessary to establish a contoured surface. The preset physical forms also typically only approximate the desired shape of the surface to be contoured, thereby decreasing the quality of the contoured surface. For example, if the physical form consists of a wire, it is virtually impossible to accurately define a desired curvature. Rather, the wire approximates the curvature by a series of successive straight segments. These and other disadvantages of prior screeding techniques have led to the desire to reduce reliance on preset physical forms.
In the past, non-concrete contouring machines have been developed for contouring three dimensional surfaces without the use of preset physical forms. These devices, however, require contact sensors for creating a profile of the subbase over which a material is placed and contoured. These devices have also been limited to earth grading, asphalt laying, or other non-concrete leveling tasks. An example of such a prior device is disclosed in U.S. Pat. No. 5,549,412 issued to Malone. This patent discloses a device for profiling and paving asphalt surfaces in three dimensions. The paving device includes a data storage device for storing the profile of the subbase to be contoured. The accuracy of the profile is dependent upon the frictional and physical characteristics of the contact sensor with respect to the subbase. The contact nature of the sensor may introduce errors into the profile creation that are undesirable.
Some prior art grading machines have also been dependent upon the profile of the subbase. Such machines can only be effectively used after the subbase has been contoured to the desired shape. This increases the amount of work required to screed a concrete surface. Some prior art grading devices have also required the generation of the profile by running the sensors over the subgrade prior to the contouring step. This profile generation step may result in additional inaccuracies due to alignment errors of the contact sensor during the contouring step when compared with the profiling step. This further increases the inaccuracies in the system.
Another disadvantage of the prior art is the required use of multiple sensors to determine the position of the contouring structure in three dimensions. For example, in U.S. Pat. No. 4,807,131 issued to Clegg, a grading system is disclosed that uses a laser reference beam in combination with a pair of wheel encoders. The laser reference beam is used to establish the vertical height of the grading blade while the encoders measure the horizontal position of the grading blade. The use of multiple sensors increases the complexity and associated cost of the grading system, and is therefore undesirable for many applications.
SUMMARY OF THE INVENTION
The present invention is an improved device and method for contouring poured uncured concrete, sand, gravel, dirt, or like loose, spreadable viscous fluid or plastic materials on the ground or on suspended decks, parking structures, or other surfaces. The present invention provides a device and method for contouring three dimensional curved surfaces without the necessity of preset physical forms on both sides of the surface to be contoured. The present invention also provides a simple and effective way for contouring surfaces that overcomes the measurement inaccuracies of various prior art machines.
In one aspect, the invention is an improved control system for controlling a contouring machine while a contouring assembly on the machine is moved over an area to be contoured. The system includes a controller for controlling the height of a first end of the contouring assembly. One of a tracking device and a target are positioned on the first end of the contouring assembly and the other of the tracking device and the target is positioned remotely from the contouring assembly. The tracking device tracks the position of the target and measures the position of the target in three dimensions as the assembly is moved over the area to be contoured. The measurement of the target is used by a controller which adjusts the height of the first end of the contouring assembly to correspond to a stored profile of the desired shape of the surface to be contoured.
According to a second aspect, the invention is a device for contouring a surface which includes a contouring assembly having first and second ends. A first sensing apparatus is positioned on one end of the assembly, while a second sensing apparatus that is different from the first sensing apparatus is positioned on the second end of the assembly. A controller adjusts the height of the first end of the assembly based on a stored profile of the desired shape of the surface to be contoured. The controller adjusts the height of the second end of the assembly based on the distance between the second end of the assembly and a reference surface along one side of the area to be contoured.
According to a third aspect, the invention is a device for contouring a surface that includes a boom movably mounted on a base. A contouring assembly is mounted at an end of the boom opposite to the base, and the assembly has a first and second end that are independently adjusted by a control system. As the contouring assembly is moved over the area to be contoured, the independent control of the first and second ends of the assembly allows the device to contour a three dimensional surface.
According to a fourth aspect, the invention is a contouring assembly for contouring a surface to its desired shape. The invention includes a support having first and second ends, an elongated contouring assembly, and a height adjustment mechanism attached to the support and the contouring assembly. The height adjustment mechanism is adapted to adjust the height of the contouring assembly with respect to the support based on the desired shape of the surface to be contoured. The contouring assembly is pivotally attached to the support and controlled by a pivot adjustment mechanism that pivots the contouring assembly about a pivot axis based also on the desired shape of the surface to be contouring.
In another aspect, the invention is a method for contouring a surface to a desired three dimensional shape and includes the steps of storing the desired three dimensional shape in a computer memory and providing a contouring assembly having first and second ends. As the contouring assembly is moved over the area to be leveled, the position of the first end of the contouring assembly is determined in three dimensions. The height of the first end of the contouring assembly is then adjusted to correspond to the height of the desired three dimensional shape. The distance between the second end of the contouring assembly and a reference surface is also determined as the contouring assembly is moved over the area to be contoured, and the height of the second en
Hallstrom Charles A.
Kieranen Carl B.
Ruonavaara Nils P.
Simula Glen R.
Waineo James D.
Addie Raymond
Delaware Capital Formation Inc.
Van Dyke Gardner, Linn & Burkhart, LLP
Will Thomas B.
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